Manually operable piezoelectric gas lighters



Filed Dec. 28, 1965 NORIO OYAMADA ET AL 3,384,786

MANUALLY OPERABLE PIEZOELECTRIC GAS LIGHTERS May 21, 1968 2 Sheets-Sheet x ITIS May 21, 1968 NORIO OYAMADA ET AL MANUALLY OPERABLE PIEZOELECTRIC GAS LIGHTERS Filed Dec. 28, 1965 2 Sheets-Sheet 2 i345 20 3o sokn United States Patent 3,384,786 MANUALLY OPERABLE PIEZOELECTRIC GAS LIGHTERS Norio Oyamada and Kenjiro Goto, Tokyo, Japan, as-

signors to Mansei Kogyo Kabushiki Kaisha, Saitamaken, Japan Filed Dec. 28, 1965, Ser. No. 516,944

9 Claims. (Cl. 31781) ABSTRACT OF THE DISCLGSURE Liquefied gas fueled lighters having a piezoelectric The present invention relates to liquefied gas fueled lighters, hereinafter briefly referred to as the gas lighter, and more specifically it relates to improvements in or relating to the igniting and burning mechanisms thereof.

It is the main object of the present invention to provide a gas lighter which obviates the necessity for using conventionally employed batteries for generating electrical sparks for igniting the combustible gas fiow.

Another object is to provide a gas lighter of the kind above referred to, capable of providing a strong mechanical striking force onto a high voltage current generating means formed in a piezoelectric crystal element assembly mounted within the lighter, at a one-touch manipulation of a manipulating member such as a push button which is however capable of returning to its non-operating position without providing a further separate manual effort.

Still another object is to provide a gas lighter of the above kind, capable of providing a high percentage of successful igniting possibilities even at the aforementioned one-touch manual manipulations.

Still funther object of the invention is to provide a gas lighter of the kind above referred to, capable of obviating fire explosion hazards.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

FIG. 1 is an equivalent electrical circuit of the electric ignition arrangement employable in the gas lighter according to the invention;

FIG. 2 is a diagram of comparative igniting characteristics according to the conventional technique and the present invention, wherein the discharge temperature has been plotted against the discharging period;

FIG. 3 is a diagram showing practical experimental data as obtained by the ignition arrangement employable in this invention, wherein the rate of ignition, percent, has been plotted against the value of the resistor as inserted in the circuit shown in FIG. 1;

FIG. 4 is a partially sectional and elevational view of essential parts of a gas lighter embodying the circuit shown in FIG. 1;

FIG. 4A is an elevational view, partially sectioned, of the top end portion of the nozzle valve which has been slightly modified so as to carry thereon an insulated conductive piece acting as an electrode.

FIG. 5 is a perspective view of a second embodiment of the gas lighter;

FIG. 6 is a bottom view of a somewhat modified gas lighter; and

FIG. 7 is a top plan view of the gas lighter shown in FIG. 5, illustrating the inside operating mechanisms thereof.

Now referring to the accompanying drawings, especially FIG. 1 thereof, 1 denotes a series of piezoelectric crystal elements, schematically illustated herein only in the form of a dotted line rectangular block and preferably made of ethylene diamine tarrate, potassium tarrate, quartz, Rochelle salt, potassium primary phosphate, ammonium primary phosphate or the like, and 2 represents an equivalent capacitance of the series elements, preferably two in their number. Further, 3 denotes the equivalent current generating couple of these elements as a whole. 5 represents a pair of spark electrodes 5a and 5b kept at a predetermined distance, for instance 2-5 mm. to each other, one of which as at 5b is mounted in close proximity of the outlet end of a burner nozzle 6. These electrodes are connected through leads 7 and 8 to the both poles of the piezoelectric crystal assembly 1. A resistor 4 is inserted in the lead 8; or alternatively in the opposite lead 7 although not shown. Capacitance 2 and resistance 4 constitute in combination a time constant circuit for the ignition arrangement as will be more fully described hereinbelow with reference to FIGS. 2 and 3.

When a hammer shock or a sudden pressure is applied onto the crystal assembly 1, a piezoelectric high pressure current will be delivered from the assembly to the spark electrodes 5a and 512 so as to generate intense sparks therebetween. When the resistance value 4 is selected to a certain value, for instance, 2-4 kiloohms for predetermined nature and dimensions of the crystal assembly 1 and the electrodes 5a and 5b having a certain spark gap of 2-5 mm., the otherwise possible are discharge may be converted to a glow discharge thanks to the provision of the aforementioned time constant circuit.

In the diagram plotted at a random scale and shown in FIG. 2, dotted curve I represents an arc discharge as appearing in the conventional technique without use of the aforementioned retardingly acting time constant means. Curve II represents a glow discharge as met in the novel technique. In the latter case, the discharging period is considerably extended, although the spark temperature is lowered. By this way, the fuel gas flow issuing from the outlet opening of burner nozzle 6, one of the spark electrodes as at 5b being arranged, as already mentioned, in close proximity of the opening, can be fed with an enough quantity of discharging spark energy to initiate the desired ignition of the gas flow, thus assuring a guaranteed burning thereof when required.

In FIG. 3, results of the ignition when employing the discharge arrangement are shown by curves III and IV with use of two kinds of commercially available piezoelectric crystal elements of Rochelle salt, taking the generating output of the couple 3 and the shape and the dimensions of the discharge electrodes 5a and 5b at predetermined conditions, yet with the resistor 4 to be variable. As shown, most favorable results have been obtained with use of 2-5 kiloohms in this experiment.

In a practical embodiment of the gas lighter illustrated in FIG. 4, 9 denotes a manually actuating member formed in a push button slidably passing through a first guide opening 24a provided through the wall of an outer casing 24, and a second guide opening 10a formed through an upper wall of an inner casing 10 which is fixedly mounted on the outer casing. A pusher rod 32 is made integral with the push button and slidably guided in a guide opening 13a formed through separating wall 13 which is rigidly connected with the inner frame 10.

The lowermost extremity of rod 32 is formed into an enlarged head 32a which is positioned loosely in a cavity 34 formed in a two-piece hammering member 33 so as to have a properly selected stroke denoted by X in the drawing. The piezoelectric assembly 1, being shown herein two-piece elements, is provided at its upper end with a metallic cap 1a so as to receive a hammering shock from the movable hammer 33 when the latter isbrought into a striking engagement with the cap, as will be more fully described hereinafter.

The piezoelectric assembly 1 is rigidly supported in an insulator support 38 in the frame 10, said support being mounted in turn on an insulator base 39 which is rigidly housed in the lower end of said frame such as by means of sticking agent, fixing screws or rivets or the like, although not shown.

Spiral spring 41 abuts on the separating wall 13 and urges resiliently the push button 9 from below, thus serving as returning resilient means.

There are a pair of click springs 42 and 42a, each being shaped in a wavy form. The outer ends of these springs pass through receiving openings 44 cut through the side walls of frame 10 and abut against stationary stops 45 rigidly fitted on the outside surfaces of the side walls, such as by fusing, while the inner ends of these springs are snugly received under compression in a peripheral groove formed on the lower piece of hammer 33 in close proximity of the lower end thereof. The configuration and strength of these click springs are so selected that when the hammer is kept its upper ineffective position as shown, they provide in combination an upwardly directing resilient urging force upon the hammer. When the hammer is lowered forcedly against this resilient urging force by manual pressure exerted upon push button 9 and passes across a predetermined imaginary plane A-A' passing through the outer abutting points 44 of the springs 42 serving as dead centers, the hammer is caused to rush towards the cap 1a at a suddenly accelerated speed by the reversed urgin force provided by the click springs. 37 denotes a take-out conductor which is electrically connected with the positive pole formed between the abutting surfaces of the upper and lower elements of the piezoelectric assembly 1 and the lead 8 extends. The uppermost and lowermost ends of the assembly 1 constitute in combination the negative pole thereof and the opposite lead 7 is connected with this pole, al though not specifically illustrated in FIG. 4.

As an alternating way of the electrical connection between the negative pole and the spark electrode 5a, metallic frame 10 itself may be utilized so as to constitute substantial part of the lead 7. In this case, support 38 and base 39 are preferably made of conductive material such as copper, instead of insulating material. A short conductive lead must in this case also be provided for connecting the negative spark electrode 5a with the metallic frame 10. A similar lead must be provided to connect electrically the upper negative pole of the assembly with the support 38 or the frame 10 itself.

16 denotes a conventional liquefied fuel gas container rigidly mounted in the casing 24. On the upper end of the container, there is provided a slidable nozzle valve 17 to which one end of an operating lever 18 is rigidly connected, while the opposite end thereof is kept in slidable engagement with a recess 56 formed in the upper constituent element of the hammer 33. This lever is pivotably mounted on a stationary support 19 which is rigidly mounted on the wall of casing 24, and designed and dimensioned to provide a retarding distance Z relative to the downward striking movement of the hammer. As commonly known, when the nozzle valve is elevated in its position, gasified fuel is delivered from the interior of the reservoir 16 through the valve and vice versa. A flexible conduit tube 22 is provided so asto establish a fuel passage between the nozzle valve and the burner nozzle 6.

When finger pressure is exerted upon the upper end of push button 9 so as to depress the latter against the spring action 41 and 42, rod 32 and its enlarged head 32a will be lowered in unison until the latter abuts against the bottom wall surface of space 34 when the rod has been moved a preliminary stroke X. When, motion is transmitted from the rod through the intermediary of its head 32a to the hammer 33, thereby the latter being accelerated to rush towards metal cap in. When the hammer has traveled a small distance Y shown in FIG. 4, the resiliently urging force provided by click springs 42 is reversed in its acting direction so that a sudden acceleration will be given to the moving hammer in its assisting direction. At last, the hammer will strike at a high speed thus accelerated against the upper surface of the cap 1a, thereby a sudden shock being transmitted through the cap to the piezoelectric assembly 1 for generating a high voltage current therefrom.

When the hammer has traveled initially at the commencement of its downward movement a predetermined distance denoted by Z, motion is transmitted to the motion-receiving end of lever 18 so that the latter will be turned in the counter-clockwise direction in FIG. 4 so as to elevate the nozzle valve 17 in the upward direction to deliver gas fuel therefrom through flexible conduit to the burner nozzle 6, for establishing a combustible gas flow at the upper outlet opening thereof. After a short time, the striking action of the hammer against the cap 1a will take place in the aforementioned way, and thus the igniting current will be conveyed to the spark electrodes 5a and 5b so as to generate intense sparks through the gap formed therebetween, thus igniting the gaseous current from nozzle 6. According to our experiments, provision of one of the both electrodes in close proximity of the outlet opening of nozzle 6 serves elfectively for promoting the igniting operation. In extreme cases, the nozzle 6 may be electrically insulated from other conductive parts of the gas lighter and formed itself as one of the both spark electrodes.

When the user utilizes the thus burning flame issuing from the nozzle 6 for igniting his cigarette or the like combustible body, finger pressure is then released from acting upon the push button and thus the accumulated energy of spiral spring 41 is released, thereby an intense returning effort being exerted from below the push button against the resilient urging action by the click springs 42. In this returning stroke, the button 9 and rod 32 will perform initially an idle movement corresponding to the idle stroke X, only whereupon the hammer is carried along in the upward returning direction by the establishment of engagement thereof with the enlarged head 32a of the related rod 32 towards its resting position shown.

In a second embodiment, shown in FIGS. 5 and 7, of the present invention formed in a table lighter, the push button has been replaced by a finger-operated, horizontally movable slide 9a and correspondingly, the motiontransmitting mechanism therefrom both to the hammer 33 and the nozzle valve operating lever 18' is somewhat modified as shown. However, the design and function of the mechanism as well as other substantial operating parts may be easily understood from the foregoing detailed description of FIG. 4 by reference to similar reference numerals and symbols each afiixed with a prime. In the present embodiment, the resistor 4 for providing an extended time period for a continued maintenance of the generated sparks is seen at the upper and left corner of FIG. 7. In FIG. 5, a side opening 46 is formed through a side wall of lighter casing 24, serving as a vent for permitting escape of accumulated combustible gas in the course of an extended use of the lighter. The gas is heavier than the atmospheric air so that a heavier layer of the combustible gas may accumulate in the lower part of the inside space of the closed casing, which will give rise to fear of explosion hazard to take place. By the provision of the side vent opening 46, such a fear as this will be effectively obviated.

In a modified embodiment shown in FIG. 6, the bottom wall of the lighter casing 24 is formed with a plurality of vent openings 47 bored therethrough, in place of the aforementioned sole opening 46.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can be applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention, and therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What we claim is:

1. A gas lighter comprising: a casing; a fuel container carried by said casing and having a supply port; a burner nozzle carried by said casing; a nozzle valve slidable on said container for controlling fuel flow through said port to said nozzle; a piezoelectric voltage source mounted in said casing; a hammer slidably mounted in said casing for movement from a first position remote from said piezoelectric voltage source through a predetermined position to a second position in contact with said piezoelectric voltage source; spark electrode means mounted in proximity of said burner nozzle and electrically connected with said piezoelectric voltage source so as to ignite gas issuing from said nozzle; first spring means resiliently biasing said hammer toward its first position; and second spring means resiliently biasing said hammer toward its first position when said hammer is between its first position and its predetermined position and resiliently biasing said hammer toward its second position when said hammer is between its predetermined position and its second position, the resilient force of said second spring means being less than the force of said first spring means.

2. A gas lighter as defined in claim 1 wherein said spark electrode means includes a pair of electrodes, one 40 of said electrodes being mounted in closer proximity of said burner nozzle than the other electrode.

3. A gas lighter as set forth in claim 2, wherein one of said spark electrodes is the burner nozzle itself which is electrically insulated from other conductive constituents of the gas lighter.

4. A gas lighter as set forth in claim 2, wherein one of said spark electrodes comprises a bored metallic cap mounted on the outlet end of said burner nozzle and electrically insulated therefrom.

5. A gas lighter as defined in claim 1 wherein said casing is formed with an opening therein for venting occasionally accumulated combustible gases.

6. A gas lighter as defined in claim 5 wherein said opening is formed in the casing in close proximity to the bottom of said casing.

7. A gas lighter as defined in claim 5 wherein said opening is formed in a bottom wall of the casing.

8. A gas lighter as defined in claim 1 further comprising a pivoted lever, one end of which is connected to said nozzle valve for opening said valve and the other end is connected to said hammer through a lost motion device, whereby said nozzle valve will be opened before said hammer is actuated.

9. A gas lighter as defined in claim 1 further comprising a resistor inserted in the electrical connection between the spark electrode means and said piezoelectric voltage source for retarding the termination of sparks generated by the spark electrode means when said hammer is brought into striking engagement with said piezoelectric voltage source.

References Cited UNITED STATES PATENTS 2,917,670 12/1959 Crownower 315--209 3,167,687 1/1965 Buithus 317-83 3,200,295 8/1965 Owens et a1. 317-83 3,218,506 11/1965 Williams et al. 315-55 3,295,024 12/1966 Newman 31786 FOREIGN PATENTS 606,498 10/ 1960 Canada.

964,945 7/ 1964 Great Britain. 1,164,141 2/1964 Germany.

BERNARD A. GILHEANY, Primary Examiner.

VOLODYMYR Y. MAYEWSKY, Examiner. 

